It has been a few years since I took a look at compression drivers and horns. I am considering a DIY project where I want to build a 'high end' fully horn loaded system. The last time that I considered this (5 to 6 years ago) my favorite compression driver and horn combination was made by TAD. What else is out there in that performance class? I've never heard Radian. Are they any good? Name your favorite compression drivers and horns and what you like about them.

I don't have any direct experience in this area (yet), but I've been following it closely as I'm very interested in a project along the lines of Tom Danleys Unity system, and I find Geddes work very interesting and compelling in terms of the approach to system to design. In that context, a couple thoughts:

- echoing what folks above have said, the 18Sound horns seem to be very very well regarded. They really seem to be close to the OS Waveguide that Geddes uses, and the subjective reports seem to bear out the lack of horn honk. For a real-world priced system, these seem to be pretty hard to beat. A 2" exit version paired with the BMS 4590/4592 would be pretty sweet.
- BMS drivers seem to get very positive reviews. I have yet to see a negative as far as I can remember, and they're reasonably priced.
- Geddes claims that in a proper waveguide, differences between 'good' compression drivers are negligible at home-audio listening levels. He did a version of his Summa using the TAD driver, and in a test nobody could reliably differentiate it from the B&C.

Having said all the above, another candidate that has just recently appeared is a 2" exit version of the Oris horn (tractrix flare I believe, but I could be wrong) paired with a modified BMS 4592ND (the coax neo unit) and a custom xover. It's available in a 'diy' package for about $3k, and the designer on the Oris forum and someone that has heard it say it's the best thing they've ever heard. He runs it from (I think) 225Hz on up. If I had $3k to spend, I'd make a serious effort to hear this as it sure looks good on paper.

kevinkr

9th June 2006 04:33 PM

Nothing very exotic in my case, a pair of vintage JBL 4333 and 2402H on top of my newly constructed Onkens.

Surprisingly free of horn colorations, although undoubtedly not perfect. I've just not started to notice any real deficits, probably haven't listened long enough and things are still breaking in. They're fast, tuneful and extremely detailed. Good dispersion throughout the room, even relatively off axis. I initially had some anxiety and misgivings over my choices, not helped by the large amount of money involved, (although compared to a TAD TH4001 these were dirt cheap.) but a little bit of rehab and things snapped into place, that and fixing several phasing/x-over issues.

The 4333 is a 2420 driver (alnico) paired with the 2312 CD horn and 2308 diffuser.

The 2402H is an annular ring bullet horn tweeter, the latest in a long series starting with the 075 which is still my favorite, at least until I can hear Fostex T900 and T925s in my own system. The purist in me currently wants a pair of 2402 with Alnico magnets.

The integration between these two drivers is superb, I am not aware of there even being two separate drivers.

I cross over at 8kHz which is just about right for these drivers, and would allow me to substitue the 2405 slot in place of the 2402H if I desired.

I designed and built the x-overs which are 2nd order butterworths and cross-over at 800Hz, and 8kHz. I used LTspice to design them as I did not have enough information to use some of the more involved x-over designers. Having looked at JBL and Altec practice extensively I figured I would get decent results with a relatively simple design.

I have provided LPADS for level adjustment to compensate for room placement effects on the bottom end and for differences in sensivity between the various drivers. My system overall exceeds 100dBSpl/w/m efficiency, but the horns are about 5dB more efficient than this.

I also listened extensively to the Altec 511B, 811B, and the multi-cellular horn atop the A7. I like the multi-cellular horn a lot, but both the other horns do exhibit the honk mentioned. This incidentally can be fixed in the x-over with somewhat complex networks.

I have not measured the 511B, but long ago measured the 811B, don't remember all of the details, but I do remember that the reponse had a huge step on the order of -6dB starting at 2kHz, and there was also another resonance or two at other places which could be trapped out. The sound was interesting, but the honk would need to be fixed, otherwise it had relatively good dispersion and high frequency response out to at least 16kHz or so.

I have heard the Fane bullet and slot horn tweeters and they are just so so, but they are inexpensive compared to the comparable JBL driver which imho outperforms the Fane product by some margin.

Carl_Huff

9th June 2006 05:21 PM

I too have been interested in Tom's Unity horn. Too bad Lambda is no longer is around. Their DIY kit was very interesting. Has anyone done a good DIY clone of the Unity horn? Any published work?

PSz.

9th June 2006 05:42 PM

I'm pretty happy with my JBL 2435H drivers on some nice tractrix horns Dr. Edgar made for me from cherry.

regards,
PSz.

dwk123

9th June 2006 06:03 PM

Quote:

Originally posted by Carl_Huff I too have been interested in Tom's Unity horn. Too bad Lambda is no longer is around. Their DIY kit was very interesting. Has anyone done a good DIY clone of the Unity horn? Any published work?

John Sheerin is still the only guy I've seen that's done a real complete version.
I'm currently running a mono quasi-Unity speaker. After several aborted attempts to get a 1" driver at the apex of a diy horn to sound anything but awful, I punted and am using the new Dayton RS52 dome mid instead. With 2 7" midbass drivers along the horn it covers 200-5k. Some tuning and tweaking to do in subsequent iterations, but initial results are VERY encouraging - sounds really good.
PM me if you want more info.

Carl_Huff

10th June 2006 04:11 AM

I had the good fortune of speaking with Bruce Edgar at the CES show a few months ago. He truly is a gentle sole that loves what he is doing. His 'salad bowl' horns work very well. After some careful listening his loudspeakers even appealed to my wife!